This invention relates to a device for mounting a rotary head obliquely on a chassis suitable for use in a digital audio tape recorder or the like device.
As a scanning system in rotary head type tape recorders such as a video tape recorder (VTR) and a digital audio tape recorder (R-DAT), a helical scanning system is generally employed. According to the helical scanning system, the drum of the rotary head is rotated obliquely with respect to the running direction of the tape and the tape is scanned while it is wound about the drum with a result that an oblique track is formed on the tape of a limited width so that maximum possible signals may be recorded on unit track length.
In the helical scanning system, it is necessary, as shown in FIG. 3 for example, to mount a rotary head 1 on a chassis (not shown) in such a manner that a rotation shaft 2 of the rotary head 1 assumes an oblique relationship with respect to the horizontal chassis.
For realizing this oblique mounting of the rotary head 1, there are used, for example, mounting adaptors 3 as shown in FIGS. 4a and 4b. These mounting adaptors 3 are so formed that an upper surface 6 thereof on which the rotary head 1 is mounted is oblique with respect to a lower surface 5 thereof which comes in engagement with a chassis 4 and screw holes 7 are formed in the upper portions of the adaptors 3 to fix the rotary head 1 with screws 8.
In such mounting adaptors 3, the screw holes 7 must be formed vertically with respect to the oblique upper surface 6 and the forming of such screw holes 7 involves difficulty. One way for achieving this is to form screw holes 7 vertically with respect to the lower surface 5 in a state before the upper surface 6 is obliquely shaped in which the upper surface is parallel to the lower surface 5 and then cut off the upper portion of the adaptor 3 obliquely to define the oblique upper surface 6 or form screw holes 7 vertically with respect to the lower surface 5 in an upper portion of the mounting adaptor 3 which is preformed with an oblique upper surface 6 and then fix the rotary head 1 by inserting tapered washers 9 between the rotary head 1 and the screws 8 as shown in FIG. 4a. Another way for forming the screw holes 7 is to form screw holes 7 in an upper portion of the mounting adaptor 3 vertically with respect to the upper surface 6 and then cut off a lower portion of the mounting adaptor 3 obliquely to define a lower surface 5 as shown in FIG. 4b.
For cutting off an upper or lower portion of the mounting adaptor obliquely, it is necessary to form such mounting adaptor by zinc or aluminum die casting or resin forming and then subject the formed product to the secondary processing. If screw holes 7 vertical to the oblique upper surface 6 cannot be formed, the tapered washers 9 are required.
The mounting adaptor 3 using the tapered washer 9 is relatively easy to make but accuracy of mounting position of the rotary head 1 is not sufficiently high.
It is, thereofore, an object of the invention to provide a device which is capable of accurately mounting a rotary head obliquely to a chassis and besides is easy to manufacture.